The Adventures of Jonathan and Jonathan
by simplymoshingintomordor
Summary: -CoLS Spoilers- Have you ever wondered what Jace and Sebastian got up to in those few weeks before Clary turned up at the apartment in CoLS? Imagine. Two teenagers. Alone in what can only be described as a bachelor pad. There's a lot of potential for trouble, right? Brace yourselves for the adventures of Jonathan and Jonathan. Things are about to get pretty insane... CANON [I WISH]


**Psst. Anyone out there?**

**I'm back, yes, after my grand two-month break. But instead of jumping straight into the BotB epilogue, I decided to warm up with this first. It's a story I've had planned since before I'd even _conceived_ BotB, pretty much the first thing that came into my head since I read City of Lost Souls, so I decided it's about time I got it down on paper. Digitally. Plus, it's Eurovision week so this is me celebrating!**

**I wanted it to read like it could literally have been a part of the book, before it dissolves into my inevitable crack.**

**Hope you guys like it and don't miss the BotB-related announcement at the end!**

**Disclaimer: I do not own TMI or any of its characters. But I like to think this is what happened.**

* * *

**Jonathan**

"_We are one now, little brother, you and I," Sebastian said._

"_We are one."_

Jace sat down on the pale leather sofa, twiddling his thumbs as he waited for Sebastian to get changed. The living room was decked out with a giant flat screen TV, a stereo system and various gaming consoles. He'd barely been there two minutes and already could see himself settling in quite nicely.

He didn't know where they were, other than that the apartment had been built by Valentine many years prior, and that it could transport itself. He'd had a brief glance out of one of the windows after Sebastian had led him through the portal, but it looked out onto nothing but a field and it was still too dark for him to make out anything more than that. The apartment may have been able to travel through space, but it couldn't traverse time. It was still the same night he'd been bonded to Sebastian.

Jace glanced down at the pink line across his palm where he'd been compelled to cut himself. It was almost healed now, just like him. He couldn't understand why he'd been so resistant before to Lilith's ritual. He'd spent all those weeks feeling unsure of himself, never knowing what was wrong with him. What he hadn't realised is that he'd felt so lost because he was _incomplete._ When Sebastian had taken his hand into his own, sharing his blood, Jace felt it. That piece of him that he hadn't even known he'd been missing. It was Sebastian. His brother. And now finally, they were whole again.

They were one.

"How do I look?" Sebastian asked, strolling into the room. Jace was already on his feet – he'd sensed him long before he'd made any sound. The bond was stronger than any connection he'd ever felt. It wasn't unlike his _Parabatai_ bond with Alec, except with Sebastian the link was all-consuming. It was as if they were a _part_ of each other, like having an extra limb, almost.

"Dry," Jace smirked, eyeing his brother's all-black attire.

"Good," Sebastian smiled back. "You wouldn't believe how annoying it's been stuck in that tank for so long. I was beginning to feel more merman than human. Though, since I'm not exactly the latter either, I don't see how that could be any worse."

"Yeah."

The boys stood facing each other, a strange silence falling upon them. They didn't exactly feel uncomfortable in the other's presence, it was quite the contrary, in fact, but the situation was still foreign to them both. Before finding out whom he really was, Jace had never spent much time alone with Sebastian. He suddenly wanted to know everything about him, to truly understand this kindred spirit, but how to go about it? He couldn't just blurt out, 'hey, are you more of a boxers or briefs kind of man?' Or could he? Maybe Sebastian wouldn't mind small talk. Perhaps, he even already knew what Jace wanted to say. They were only just beginning to understand this new bond between them, after all.

"Why don't we start from the beginning?" Sebastian suddenly piped up. He held out his hand, devoid of blood this time. "Jonathan Christopher Morgenstern."

Jace reached out and took it, before introducing himself. "Jonathan Christopher..." He hesitated. Who was he now? He wasn't a Wayland, that was for sure. Clary had said he was a Lightwood, but suddenly that didn't feel so right. Technically he was a Herondale, but that name hadn't meant much to him a few short months ago. That _should_ have been what he said, but looking into Sebastian's black eyes, he felt another name tugging at him instead. A name he never thought he'd want to take, and yet he'd been wearing it all along. "Jonathan Christopher Morgenstern."

Yes. Now, that felt right.

Sebastian…or Jonathan, he should say, had called him little brother, after all. He'd been raised by Valentine just the same. He was a Morgenstern.

"Hmmm…" Jonathan pursed his lips. "That may be problematic."

"Why's that?"

"We can't both be Jonathan Christopher Morgenstern."

"But you called me brother…" Jace's heart sank. He'd thought Jonathan would be pleased.

"And you are my brother, Jace. In so much more than blood. But don't you think it'll get confusing, both of us being called Jonathan?"

"How's that?"

"Like, if one of us ordered something and the package read 'Jonathan Christopher Morgenstern,' how would we know who it was for?"

Jace couldn't help but agree. Jonathan was so wise.

"Or if we went to Starbucks and I liked decaf, how would we know whose drink was whose? I might accidentally drink your coffee and go off the rails," Jace added. Caffeine did very strange things to him. It was almost as bad as faerie drinks.

"I don't know what that means, but yes," Jonathan nodded. Or should he say Sebastian? "This is a problem indeed, but how to fix it? We'll have to find a new name for you."

"Me? Why me?"

"Because I was born first, so I was Jonathan Christopher Morgenstern first."

"That's reasonable."

"How about Christopher? That's still part of your name."

"Christopher?" Jace let the name roll off his tongue.

"Yeah, Christopher. Introduce yourself again, see how it feels."

Jace extended his hand, preparing himself.

"Hello, I'm Christopher…Jonathan Morgenstern?"

"Why did you add the Jonathan?"

"I don't know," Jace shrugged. "I just figured since you're Jonathan Christopher, I could be Christopher Jonathan. Like, JC and CJ…" He smiled, liking the ring of it.

"We're not some boyband, brother."

"Of course not, sorry."

Jace stared at the ground as Jonathan paced back and forth in front of him. Suddenly, he paused mid-stride.

"I have an idea! Follow me!" Jonathan beckoned Jace through to the other side of the living room, and then led him down a corridor that lit up as they walked through. He stopped by a door to his right and pushed it open, flicking on the light switch. Jace followed him through into the guest bedroom, hanging awkwardly by the doorway. Built-in wardrobes, all with mirrored doors, dominated one side of the room.

"Come stand here," Jonathan said, waving Jace forward. They stood side by side, gazing at their reflections. "Okay, now try saying your name again. You're starting afresh now, we both are, so we have to feel comfortable with our new identities."

"Will you go first?"

"Sure," Jonathan pulled himself up to his full height, staring straight ahead. "Hello, I'm Jonathan Christopher Morgenstern." The words fell flat. Something wasn't right. Jonathan adjusted his stance, sticking his hands in his pockets for a more casual look. "Hey, I'm Jonathan." Still not right. He ruffled his hair, letting some of the strands fall across his face. "JC, any last words?" Nope.

"What's wrong?" Jace tore his eyes away from his own reflection to look at Jonathan's.

"I'm Jonathan, but I don't feel like a Jonathan."

"Why not?"

"I don't know," Jonathan shrugged. "Valentine's called me by that name for my whole life. I was Sebastian for a little bit, yes, but I knew that was just a cover. I never forgot who I was. But…" His eyes lit up. "Maybe I don't want to be who I was. After all, what was I, other than Valentine's woefully damaged son? His puppet? Jonathan Christopher Morgenstern was his experiment. His toy. But I've outgrown that. I've outgrown him. I am Lilith's child, not his. I'm free of him." Jonathan took a step back, the realisation dawning on him. "I'm free of him! Don't you see, Jace!? He's gone. Dead. He can't control us if he's dead. He's not watching us anymore. He can't control us. I can do _whatever _I want!" Jonathan turned around frantically, bursting with energy. He grabbed the closest thing to him, which happened to be the duvet of the four-poster bed, and dragged it onto the floor in one fell swoop. "How do you like that, eh, father!? Your precious room for your precious wife, a MESS!"

Jace inconspicuously tried to fold up the duvet as Jonathan continued whirling his way through the room like a tornado, throwing things about. He liked knowing that Jonathan was happy, but his own compulsive need to be tidy was winning through. Seeing clothes strewn all over the floor weren't exactly his idea of fun. Unless those clothes happened to be Clary's and they were there for a whole other reason.

"Isn't this fantastic!?" Jonathan continued on his rampage, stopping only to survey the state around him. "There's no one to stop us now an- what are you doing?"

Jace dropped the duvet at once.

"Nothing." He rattled one of the bed posts. "Disaster, wahey!"

"Did you just fold up that duvet?"

"What?" Jace nudged it with his foot, attempting to unroll it. "No, it just fell into that position."

"Oh dear," Jonathan shook his head, walking towards Jace and placing a hand on his shoulder. "Why didn't you tell me it was this bad?"

"What's bad? Nothing's bad. Everything's fine," Jace chuckled nervously. "Freedom!"

"This is his doing, can't you see that? He was the one who drilled this need for order into you. It's just one of the many scars he's left behind. But it's okay now, little brother. He can't force you to do anything anymore." Jonathan placed his other hand on Jace's other shoulder, staring at him with concern. "Unfold the duvet."

"Is that really nec…"

"Do it."

Jace couldn't find it in himself to argue. Once Jonathan had stepped back to watch him, he crouched down and held the edges of the duvet with trembling hands.

"Go on. It's okay."

Ever so slowly, Jace pulled the duvet out of its immaculate form and threw it across the room, wincing as it took down a lampshade on its way to the ground.

"Very good," Jonathan commended. "I liked the extra effect with the lamp there. Very nice. This is just beginning, little brother, do you see? We weren't brought together to continue our misguided father's work. Valentine was probably the worst guardian in all of parental history! We're here to carve out our own path, free of him. Free of the clave. Where he wanted order, a world teeming with Shadowhunters, I'll bring chaos. Where he had his Circle, I'll have…I'll have…The Line!"

"The Line?" Jace sounded sceptical.

"Yes," Jonathan bobbed his head, the plans taking shape in his head. He would not continue his father's legacy, he'd destroy it. He'd bring the entire Shadowhunter race to its knees and eradicate them, once and for all. The Demon boy and the Angel boy. Retribution at last. "Why do you think he picked that name for his group? A circle is a definite shape. It is enclosed. It can be controlled. But a line? A line can be anything it wants to be. It can be vertical or horizontal, straight or uneven. And what happens when a line penetrates a circle!? It _divides _it. That's what we'll do, little brother. We will divide. We will bring this entire society to the ground and strike it through like the mistake it is. That will be the power of the Line."

Jace preferred to stay silent while Jonathan continued to have his epiphany, but he could feel the anticipation bubbling up inside him all the same. Jonathan's mood was infectious, setting the whole room aglow.

"And we'll start with our names. I'm not Jonathan Christopher Morgenstern and neither are you. That's the name _he_ gave to us. From now on, you'll call me Sebastian. I don't care if he was just a cover. That cover helped to bring down the defences of the most heavily fortified city in the world. I brought glory to the name Sebastian Verlac and I alone. If I want to be French, I will be French! I will wear the Verlac name with pride. And what shall I call you?"

"Jace," Jace sighed with relief, the familiarity of the name bringing him comfort.

"Sebastian and Jace," Sebastian smiled wickedly. "The Line to end all other Lines."

"The Line to end all other Lines," Jace agreed, smiling back.

The Shadowhunter world wouldn't know what had hit them.

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**Oh indeed.**

**So what did you think? This is my first completely non-BotB-related fic (on this account ;)) so it was just as nerve-wracking diverting from the world I've become so used to over this past year. Feedback would be awesome.**

**It's going to become more a series of one shots rather than a running story, but we'll see how it pans out if you guys like it.**

**As for something that is BotB-related: I will be posting the Epilogue THIS WEEK. Oh yes. You have waited long enough so I managed to find some time during my revision to write it up. I'll be uploading it at around 11PM GMT on this Sunday (11th May) and I'll be online for a little while afterwards so I can actually stick around and talk to you guys for a bit. Spread the word!**

**Till the next time...**

**smim **

**xx**


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